As I am the type who spends so much time reflecting, I often wonder about what could have been. What would happen if I stayed where I was? What would happen if I pursued that particular thing more eagerly? What missed opportunities have I had? What mistakes have I made? Truth be told, it is great to learn from your past, but dwelling on it does nothing but fill time. Truly forgive yourself for mistakes you've made. Realize that you're human and can't do everything. The best thing you can do is live in the present, and create for yourself a better tomorrow.
Unfortunately, many of us, myself included, spend so much time worried about what the future holds, and we miss out on enjoying the good things now. Remember that there is a beautiful world out there with so much to discover and experience. Think about and enjoy the past times that make you happy.
I leave you with this final statement: the thought of something bad happening is often worse than the occurrence itself.